Project Summary Black men who have sex with men (BMSM) experience disparities along the HIV care cascade and there is evidence that sexually transmitted infections (STI) are one of the contributing factors. Self-testing technologies offer convenience and privacy and address barriers to clinic-based testing and has been shown to be well accepted by MSM. Despite these potential benefits and reports of willingness to use free self- testing, uptake has been low due to barriers such as concerns about accuracy of the tests, apprehension to collect specimens, low risk perception and desire for counseling. Studies have also shown that BMSM report willingness to distribute self-testing kits to peers, yet interventions are needed to address barriers which include: fear of peer reactions and anticipated negative effects on relationships. In the proposed study, we will test a 3 session intervention that trains BMSM as Peer Mentors to use HIV and STI (gonorrhea, chlamydia and syphilis) self-testing and promote uptake to peers and sex partners. Study aims are to examine feasibility, reach and preliminary efficacy of the intervention. We will examine facilitators and barriers to peer outreach, number of peers and sex partners referred to the self-testing website, their testing and risk characteristics and uptake of self-testing among BMSM and their peers/sex partners. We will enroll 140 BMSM who will be randomly assigned to the Peer Mentor intervention or self-testing website only. Inclusion criteria for BMSM are: (a) self-report male sex, (b) condomless anal sex with >1 male in the prior 6 months, (c) Black race, (d) aged 17 or older (based on FDA approved age of HIV oral test kit), (e) internet use at least once a week. BMSM in both conditions will be given coupons with the self-testing website link and unique log-in codes to give to peers/sex partners (aged 17 or older). Peers/sex partners who access the website will provide consent, complete a web-based baseline survey to assess HIV and STI testing history and sexual risk behavior and will be able to request self-test kits to be mailed. BMSM and their peers/sex partners will complete a 3 month follow-up survey to assess HIV and/or STI linkage to care, changes in norms on self-testing, willingness to link to PrEP, and sexual risk.